Bulldozer



March 6, 1945.

T. R. PAULSEN BULLDOZER' I Original Filed Aug. 9,

1941 -2 Sheets-Sheet 2 ATrORNEYS Reissued Mar. 6, 1945 'y i Re; 22,6113

UNITED 'STATES PATENT OFFICE lsunmozaa l Thomas lt. Paulsen, SouthMilwaukee, Wis., as-

lignor, by mesne assignments, to Laplantl Choate Manufacturing Co. Inc.,Cedar Rapids, Iowa. a corporation of Delaware original Nn. 2,321,615,amd June 15, 194s, serial No. 406,090, August:` 9, 1941.

Application for reissue July Z0, 1944, Serial No. 545,794

3 Claims. (Ci. 37-145) My invention relates to new and usefulimprovements in bulldozers, and more particularlyl to that type ofbulldozer in which the scraping Ibladeis pushedahead of-a tractor.

Such devices are usually designed forA attachment to some conventionaltype of tractor. They consist of a blade, two arms pivoted on thetractor for pushing the blade, and means to raise and lower either armwith a certain degree of independence from the lowering and raising ofthe' other arm. 'I'he last-mentioned means usually consists of one ortwo hydraulic cylinders -actunated by a pump driven by the engine of thetractor.

If two such cylinders are used, it is convenient to have them controlledby a single control- V are deilned in the appended claims, and of whichone embodiment is exemplified in the accompanying drawings, which arehereinafter particularly described and explained.

Throughout the description, the same reference num-ber isapplied to thesame memberor to similar members. y

Figure! is a sideelevation of a tractor, bulldozer and ripper, embodyingmy invention, showing in full lines the mechanism in bulldozing psition,and'in dotted lines the mechanism in ripping position. y

Figure 2 is a plan view of my invention. l

Referring now to the figures, we see that Il is a conventional tractor,mounted on creeping traction I2. These creeping traction elements arepivoted on propelling shaft I3, and their front ends have considerablefreedom to rise and fall to conform to unevenness of the ground. y

Pivoted to each traction element l2 at I4 is a forwardly projecting armI5. These arms support and impel a scraper blade- I6.

On each side of the tractor there is a link Il pivoted to the rear ofthe tractor at I8, and a link Il pivoted to the creeping traction at 20.These two links are pivoted together at 2l, and at this point is alsopivoted the elbow of a bell-crank 22.

The front end of each bell-crank supports one side of the blade I6through a link 23.

There are two cylinders 24, each pivoted at 25 on one of the links I'I.The piston vrod 26 of each cylinder is pivoted at 2'1 to the short armof the bell-crank 22.

The rear ends of the twoA cylinders are con-- nected by a pipe 28, fromwhich a pipe 29 leads to a control-Valve 33. The front ends of the twocylinders are similarly connected'by a pipe 3|, from which a pipe 32leads to the control-valve 30.

The control-valve may be of any conventional design, the details ofwhich are not shown as they form no part of my invention. But the valveshould have four positions, namely: (l) to pump from the rear of thecylinders into the front, and

, thus retract the pistons; V(2) to pump' from the front of thecylinders. into the rear, and thus thrust the pistons out; (3) to closeboth pipe 29 and pipe 32, and thus hold the pistons; and (4) to openpipe 29 to pipe 32, and thus permit free oating of the piston.

From the valve a pressure pipe 33 and a suction pipe 34 lead to a pump35, actuated in any conventional manner by the main engine of thetractor. From a iluid tank 33, there runs to suction pipe 34, a pipe 31with a check valve 33, for the purpose of keeping the system always lledwith fluid. From the suction pipe 34 to the tank 36, there runs a pipe44 with a pressure relief valve 45 to permit compensation for the spaceoccupied by the piston rods 26 within the cylinl ders 24 when thepistons are being retracted and yet hold them against unintendedretracting.

It will be noted that pivot point I4, for the rear ends of my arms I5,is on the ends of the rear axle of the creeping traction. This isadvisable, but not' essential.

Upwardly extending from each push-arm I'5, adjacent this point I4, is abracket 4S, to which is pivoted the elbow of a bell-crank-sh-aped ripperarm 4l. This pivot need not be actually on push-arms I5, but preferablyshould be adjacent point I4. Whenever in the claims, I use the phrasepivotally supported by it is intended to be generic to the pivotalsupport of ripper arm 41 on the push arm I5, and any other equivalentsupport therefor.

Ripper arms 4l carry a cross piece 48, which in turn carries the ripperteeth 49. Pivotally supripper armI 4l has a cooperating hole whereby itcan be secured to this link 50, by any appropriate means such as a bolt.

The rearward portion oi' the-ripper assembly carries appropriate means,such as a chain l2, for

- securing the ripper in elevated position, as by hooking the chain overthe projecting end of pivot i8 on the tractor. But any other comparablemeans may be employed for this purpose. Y When not in use, link 50 canlie forward in bracket 53 on push-arm il. v

The operation of my invention is as follows:

WhenY chains 52 are hooked over pivots I8, and links 5l are lying inbrackets` 53, my combined bulldozer and ripper operates as aconventional bulldozer. ,i .Y

To operate it as a combined' ripper and bull-,- dozer, the blade I6 islowered'to the ground, as shown in full lines in Figure 1. Links 5I) arethen swung up and pivotally secured to ripper arms 41, and chains 52 aredetachedirom pivots I8.

Raising the bulldozer blade now lowers th ripper, and vice versa. l

It will be noted that, by having the blade-operating means operate theripper through operating the blade and thence through a connectionbetween the blade vand the ripper, rather than to have a commonoperating meansdirectly operate both instrumentalities, I am enabled toadapt a conventional bulldozer to my invention.

It will further be noted that the raising of the bulldozer blade lowersthe ripper, and vice versa; rather than to have the two.instrumentalities rise simultaneously, and lower simultaneously.

Other tools than the blade Il could be carried by the push-arms I5.

It is to be understood that the same principles can be employed toattach my ripper to any other comparable form of dirt-moving equipment,for control by the same controls, selectively or simultaneously.

Having now described and illustrated one form of my invention, I wish itto be understood that my invention is not to be limited to the specificform or arrangement vof paris hereinbefore de- 's scribed except asspecified in the appended claims.

- pivotally supported by one of the push-arms adja- `cent its rear end;a link pivoted on each pusharm; means on each push-arm for supportingits .v linkin inactive position; means for operatively connecting eachlink to its ripper arm; a transverse tooth-carrying member, supported bythe Vripper-arms, ripper teeth carried by this transverse member; andmeans for supporting the ripper arms, directly by the tractor, ininactive elevated position.

2. In a combined tool and ripper, for attachment to a tractor, thecombination of a pair of push-arms; means supportable by the tractor,for raising and lowering these arms; a tool, carried by these arms; tworipper arms; the pusharm and the ripper arm oneach side being pvotallysupported by the tractor at points closely adjacent to each other; alink pivoted on each push arm; means for operatively connecting eachlink to its ripper arm, in such manner that the raising and lowering orthe push-arm will act y through the link to change the elevation of theripper arm; ripper teeth `carried by the ripper arms; and means forsupporting the ripper arms,

directly by the tractor in inactive elevated po- THOMAS ln. PAULSEN.

